Total Complaints
10 filings
TOYOTA PRIUS · model year
10 NHTSA complaints, 3 crash reports for this specific cohort.
NHTSA overall rating
5 / 5 ★
New Car Assessment Program
The 2021TOYOTAPRIUS carries 10 consumer safety complaints in NHTSA's Office of Defects Investigation database for this specific model-year cohort. Within that volume, owners reported 3 crashes, 0 fires, 0 injuries, and 0 fatalities. For crash performance, NHTSA's New Car Assessment Program gave this cohort an overall 5/5 rating, with 4/5 front crash, 5/5 side crash, and 4/5 rollover scores derived from standardized barrier and dynamic tests.
Component-level analysis is where model-year complaints become actionable: the top complaint category for the 2021 PRIUS is engine with 2 filings, followed by wheels (1) and fuel/propulsion system (1). Concentration in one or two component groups is the classic signature of a systemic defect; a flat distribution usually reflects normal aging, warranty complaints, or isolated build-plant variability.
NHTSA currently has 51 investigation files overlapping the 2021 PRIUS, and 1 remain open. Owners comparing this cohort against neighboring years should pair the counters above with the complaint-by-year trend on the parent model page — a spike in a single year often tracks to a platform refresh, a new transmission supplier, or an updated ECU calibration. Use the related-complaint feed below to read raw owner narratives before deciding whether any pattern here affects your specific use case.
Total Complaints
10 filings
Crashes Reported
3 reports
Source
NHTSA ODI
Federal complaints database
At or below the fleet median complaint volume.
| Component | Count |
|---|---|
| ENGINE | 2 |
| WHEELS | 1 |
| FUEL/PROPULSION SYSTEM | 1 |
| UNKNOWN OR OTHER | 1 |
| SERVICE BRAKES | 1 |
| ELECTRICAL SYSTEM | 1 |
| FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL | 1 |
| LANE DEPARTURE: ASSIST | 1 |
| VEHICLE SPEED CONTROL | 1 |
The contact owns a 2021 Toyota Prius. The contact stated while driving approximately 35 - 45 MPH, the vehicle independently accelerated. The brake pedal was depressed but failed to stop the vehicle immediately. The contact swerved around the vehicle in front and ended up on the opposite side of the roadway. The contact attempted to avoid oncoming traffic and swerving around all the other vehicles and ended up in a ravine. The contact's husband depressed the START/STOP button from the passengerâs side to turn off the vehicle, enabling the vehicle to come to a stop. The contact restarted the vehicle and continued to drive the vehicle to the dealer at slow speeds. The dealer was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was made aware of the failure by the dealer. The failure mileage was 56,000.
Mileage: 56,000
The Lane keeping assist used in radar cruise control mode during some drive cycles will attempt to maintain the vehicle position to the far extreme of the lane and in some cases actively veer out of the lane. My safety ant others can be put at risk when the vehicle behaves outside of its design parameters like this. To solve the issue the vehicle must be pulled over, turned off, then restarted. After the restart it will resume functioning normally, maintaining lane positioning as intended within the limits of the system. The trigger for this is unknown but could be speculated that it is drive cycle dependent and may start during initialization. The problem has not been reproduced by a dealer or service center due to its intermittent nature. There are no warning indicators or lamps on when this occurs.
The Lane keeping assist used in radar cruise control mode during some drive cycles will attempt to maintain the vehicle position to the far extreme of the lane and in some cases actively veer out of the lane. My safety ant others can be put at risk when the vehicle behaves outside of its design parameters like this. To solve the issue the vehicle must be pulled over, turned off, then restarted. After the restart it will resume functioning normally, maintaining lane positioning as intended within the limits of the system. The trigger for this is unknown but could be speculated that it is drive cycle dependent and may start during initialization. The problem has not been reproduced by a dealer or service center due to its intermittent nature. There are no warning indicators or lamps on when this occurs.
The car accelerated without my foot on the accelerator, brake did not respond, and I had to drive through grass and a rock-filled ditch until after about 10 seconds the car returned to my control.
The car accelerated without my foot on the accelerator, brake did not respond, and I had to drive through grass and a rock-filled ditch until after about 10 seconds the car returned to my control.
The car accelerated without my foot on the accelerator, brake did not respond, and I had to drive through grass and a rock-filled ditch until after about 10 seconds the car returned to my control.
CARBON MONOXIDE SEEPS INTO THE PASSENGER CAR BUT DILLER CANNOT FIND IT AND DID NOT HAVE TOOLS TO DETECT CO LEVEL IN THE CAR. I CAN'T USE THIS CAR BECAUSE WAS POISONED MANY TIMES AND AFTER A SECOND CHECK-UP, THE LEVEL OF CO BECOMES HIGHER SO I CAN'T DRIVE THE CAR WITHOUT POISONING. PLEASE HELP ME. I AM WORRYING TO SELL MY CAR BECAUSE OTHER DRIVER WILL GET INJURY. THIS IS THE NEW CAR ONLY 7000 MILES.
Mileage: 5,200
CARBON MONOXIDE SEEPS INTO THE PASSENGER CAR BUT DILLER CANNOT FIND IT AND DID NOT HAVE TOOLS TO DETECT CO LEVEL IN THE CAR. I CAN'T USE THIS CAR BECAUSE WAS POISONED MANY TIMES AND AFTER A SECOND CHECK-UP, THE LEVEL OF CO BECOMES HIGHER SO I CAN'T DRIVE THE CAR WITHOUT POISONING. PLEASE HELP ME. I AM WORRYING TO SELL MY CAR BECAUSE OTHER DRIVER WILL GET INJURY. THIS IS THE NEW CAR ONLY 7000 MILES.
Mileage: 5,200
CARBON MONOXIDE SEEPS INTO THE PASSENGER CAR BUT DILLER CANNOT FIND IT AND DID NOT HAVE TOOLS TO DETECT CO LEVEL IN THE CAR. I CAN'T USE THIS CAR BECAUSE WAS POISONED MANY TIMES AND AFTER A SECOND CHECK-UP, THE LEVEL OF CO BECOMES HIGHER SO I CAN'T DRIVE THE CAR WITHOUT POISONING. PLEASE HELP ME. I AM WORRYING TO SELL MY CAR BECAUSE OTHER DRIVER WILL GET INJURY. THIS IS THE NEW CAR ONLY 7000 MILES.
Mileage: 5,200
WHILE DRIVING ON THE I 4 WE HAD A BLOWOUT ON THE REAR PASSENGER TIRE. THE CAR HAD LESS THAN 200 MILES ON IT SO IT WAS BRAND NEW. THE DEALERSHIP FOUND OBJECT IN THE TIRE THAT COULD HAVE CAUSE THE PROBLEM THE ONLY CONCLUSION I COULD COME TO IS THAT THIS TIRE WAS DEFECTIVE. THE DEALERSHIP SAID I COULD HAVE RUN OVER A LARGE OBJECT OR A LARGE POTHOLE, WHICH I DOUBT.
Mileage: 190
Data as of 2025. Sources: NHTSA Office of Defects Investigation (ODI) complaints database, NHTSA recall campaign API, NHTSA NCAP crash-test ratings, and NHTSA FARS for fatality cross-reference.
Read our methodology — how this data is sourced, computed, and verified.